Elasticity as a measure for online determination of remission points in ongoing epidemics.

The correct identification of change-points during ongoing outbreak investigations of infectious diseases is a matter of paramount importance in epidemiology, with major implications for the management of health care resources, public health and, as the COVID-19 pandemic has shown, social live. Onsets, peaks, and inflexion points are some of them. An onset is the moment when the epidemic starts. A "peak" indicates a moment at which the incorporated values, both before and after, are lower: a maximum. The inflexion points identify moments in which the rate of growth of the incorporation of new cases changes intensity. In this study, after interpreting the concept of elasticity of a random variable in an innovative way, we propose using it as a new simpler tool for anticipating epidemic remission change-points. In particular, we propose that the "remission point of change" will occur just at the instant when the speed in the accumulation of new cases is lower than the average speed of accumulation of cases up to that moment. This gives stability and robustness to the estimation in the event of possible remission variations. This descriptive measure, which is very easy to calculate and interpret, is revealed as informative and adequate, has the advantage of being distribution-free and can be estimated in real time, while the data is being collected. We use the 2014-2016 Western Africa Ebola virus epidemic to demonstrate this new approach. A couple of examples analyzing COVID-19 data are also included.

El punto de remisión de una epidemia localizado por su elasticidad: aplicación a la primera ola del COVID-19 en Chile / The remission point of an epidemic identified by elasticity. application to the first wave of covid-19 in Chile

INTRODUCCIÓN. La detección de cambios en las características de un proceso aleatorio, conocido como el problema del cambio, se ha convertido en un área de investigación estadística en rápido desarrollo. La correcta y rápida detección de los cambios es relevante en muchas situaciones reales, en particular, en Epidemiología. MATERIALES Y MÉTODOS. Como nueva métrica para determinar el momento efectivo de remisión de una epidemia (momento del cambio), se utiliza el concepto de elasticidad de una distribución de probabilidad, y se aplica a la reciente pandemia COVID-19 en Chile. RESULTADOS. La aplicación evidencia que existe una demora entre el día "pico" o día con el mayor número de casos, con el de "remisión" identificado por la elasticidad. En ese lapso temporal, entre pico y remisión, no deben suavizarse las medidas de control de la epidemia. Se obtiene una diferencia de 20 días entre los puntos de remisión de las series de contagios y muertes. Esta cifra puede interpretarse como una estimación de la supervivencia para los fallecidos durante la primera ola de COVID-19 una vez detectada en ellos la enfermedad. La comparación de los resultados de la aplicación con la de otros países sudamericanos muestra en ellos idéntico resultado que el observado en Chile, si bien con tiempos de demora entre pico y punto de remisión sensiblemente mayores. DISCUSIÓN. La medida usada en este trabajo es fácil de comunicar, no exige la formulación previa de hipótesis sobre el comportamiento de los datos y puede ser aplicada en tiempo real, tal y como se van conociendo los datos. Estas características de fácil aplicabilidad e interpretación, generando resultados razonables, la hacen atractiva e interesante para el estudio del cambio en series epidemiológicas.

INTRODUCTION. Detecting changes in the evolution of a random process, known as the problem of change, has become a quickly developing area of statistical research. The correct and rapid detection of changes is relevant in many real-life situations, particularly in epidemiology.MATERIALS AND METHODS. As a new metric to time-locate the moment of remission of an epidemic (moment of change), the concept of the elasticity of a probability distribution is applied to the recent COVID-19 pandemic in Chile.RESULTS. The application shows that there is a delay between the "peak" day, or day with the highest number of cases, and the "remission" day as identified by elasticity. In this period, between peak and remission, the epidemic control measures should not be relaxed. A difference of 20 days is obtained between the remission points of the series of infections and deaths. This figure can be interpreted as an estimate of survival time for those diagnosed with the disease who subsequently died during the first wave of COVID-19. Comparing the results of the application with that of other South American countries, we observe the same result as that attained for Chile, although with significantly longer delay times between the peak and the point of remission.DISCUSSION. The measure used in this study is easy to communicate, does not require the prior formulation of hypotheses about the behaviour of the data and can be applied in real time, as and when the data is known. These characteristics of easy applicability and interpretation, generating reasonable results, make the application convenient for the study of change in epidemiological series

Factores predictores de riesgo de repetición de intento de suicidio en una muestra de pacientes ambulatorios / Relevant risk factors of repeated suicidal attempts in a sample of outpatients

INTRODUCCIÓN: El suicidio representa un problema destacado en la actualidad; una línea de prevención e intervención es la detección de los factores de riesgo. En este estudio se pretende identificar los predictores de suicidio en pacientes con repetición de intento de suicidio (RIS) en seguimiento en un programa de intervención intensiva. MATERIAL Y MÉTODOS: La muestra la forman los pacientes incluidos en el programa de intervención intensiva por intento de suicidio. Se registran las variables sociodemográficas y clínicas, los abandonos, la RIS, las faltas a consulta y los resultados obtenidos en las escalas de depresión y desesperanza de Beck a lo largo de los 12 meses de seguimiento en el programa (inicial, 6 meses y 12 meses). Análisis estadístico: La asociación entre RIS y variables cualitativas de estudio se realizó empleando Chi-Cuadrado y para las cuantitativas T-Student. Los análisis se hicieron utilizando el software SPSS 19.0. El estudio ha sido aprobado por el Comité Autonómico de Ética de la Investigación de Galicia. RESULTADOS: De la muestra de 319 pacientes, 29 (9%) realizan una RIS, 22 (76%) durante los primeros 6 meses del programa. De los pacientes con RIS, 7 (24%) tienen historia de intento previo durante un periodo inferior a 180 días al intento índice (p = 0,033). La intoxicación medicamentosa fue el método más empleado pues fue utilizada en el intento índice por 240 pacientes (76%). Veintisiete (93%) mantienen el método en la RIS (p < 0,001). CONCLUSIONES: La sobreingesta de fármacos como método de intento y reintento, y el tiempo transcurrido desde el intento previo son los factores de riesgo destacados asociados a la RIS, de ahí la importancia de identificar a los pacientes con historia de intento de suicidio para llevar a cabo una intervención más intensiva y un ajuste adecuado del tratamiento sobre todo en los primeros 180 días

INTRODUCTION: Suicide is, at present, an important global public health problem; detection of risk factors can be used as a method for prevention and intervention. This study aims to identify predictors of suicide in patients with suicidal attempt retry (SAR), who are followed-up an in the Intensive Intervention Program (PII). MATERIAL AND METHODS: The sample includes patients followed up at the Intensive Intervention Program because of a previous suicidal attempt. The following variables were collected during the 12 months follow-up (baseline, 6 months and 12 months): Repeated attempts, socio-demographic and clinical variables, lack of adherence and the Beck Depression Inventory and Hopelessness Scale. Statistic analysis: The association between SAR and qualitative study variables was performed using Chi-Square and for the quantitative, T-Student was used. The analysis was carried out with the software SPSS 19.0. The study has been approved by the Research Ethics Committee of Galicia. RESULTS: Of the 319 patients, 29 (9%) of them committed a new suicidal attempt, 22 (76%) of these new attempts happened during the first 6 month of the Program. Of those who repeat the attempt, 7 (24%) have a history of a previous attempt that precede the basal attempt (P=.033) in less than 180 days. Medication overdose is the most used method, as it was used by 240 of the patients (76%). 27 (93%) kept drug overdose as their retry method, also reaching significance(P<.001). CONCLUSIONS: Overdose as a method of attempt and re-attempt, and the time elapsed from the previous attempt, are the highlighted risk factors associated with repeated suicidal attempts. For this reason, it is crucial to identify patients with a new suicide attempt so that a more intense intervention and drug treatment control is delivered during the first 180 days

Relevant risk factors of repeated suicidal attempts in a sample of outpatients. / Factores predictores de riesgo de repetición de intento de suicidio en una muestra de pacientes ambulatorios.

INTRODUCTION: Suicide is, at present, an important global public health problem; detection of risk factors can be used as a method for prevention and intervention. This study aims to identify predictors of suicide in patients with suicidal attempt retry (SAR), who are followed-up an in the Intensive Intervention Program (PII). MATERIAL AND METHODS: The sample includes patients followed up at the Intensive Intervention Program because of a previous suicidal attempt. The following variables were collected during the 12 months follow-up (baseline, 6 months and 12 months): Repeated attempts, socio-demographic and clinical variables, lack of adherence and the Beck Depression Inventory and Hopelessness Scale. STATISTIC ANALYSIS: The association between SAR and qualitative study variables was performed using Chi-Square and for the quantitative, T-Student was used. The analysis was carried out with the software SPSS 19.0. The study has been approved by the Research Ethics Committee of Galicia. RESULTS: Of the 319 patients, 29 (9%) of them committed a new suicidal attempt, 22 (76%) of these new attempts happened during the first 6 month of the Program. Of those who repeat the attempt, 7 (24%) have a history of a previous attempt that precede the basal attempt (P=.033) in less than 180 days. Medication overdose is the most used method, as it was used by 240 of the patients (76%). 27 (93%) kept drug overdose as their retry method, also reaching significance(P<.001). CONCLUSIONS: Overdose as a method of attempt and re-attempt, and the time elapsed from the previous attempt, are the highlighted risk factors associated with repeated suicidal attempts. For this reason, it is crucial to identify patients with a new suicide attempt so that a more intense intervention and drug treatment control is delivered during the first 180 days.

Evaluation of an intensive intervention program in suicidal behaviour.

INTRODUCTION: Suicide is a public health problem. Consumed suicides reach 1 million cases per year worldwide and it is estimated that the number of suicide attempts is 10 to 20 times higher. The aim of this study was to evaluate the effectiveness in reducing repeat suicide attempts in a program for the prevention of suicidal behavior: Intensive Intervention Program (IIP). METHODS: We performed a study that compared a cohort of patients exposed to IIP intervention with another cohort of patients exposed to conventional therapy. The sample was made up of 191 patients, 89 in the treatment group and 102 patients in conventional treatment group, with a 12-month follow-up. RESULTS: Relapse occurred in 20.6% of patients receiving conventional treatment relapse compared with 10% in the treatment group (p=0.047). Patients treated in the program had a 2.88 times lower risk of relapse (p=0.015), this being independent of the number of previous attempts, age, gender, need for admission after the index attempt and aggregated diagnosis. CONCLUSIONS: The results show that subjects who are treated in the IIP relapse less, need fewer admissions and the time elapsed between the treatment and the first repeat suicide attempt is greater.

Evaluación de un Programa de Intervención Intensiva en Conducta Suicida / Evaluation of an Intensive Intervention Program in Suicidal Behaviour

Introducción: El suicidio es un problema de salud pública. El suicidio consumado asciende a 1 millón de casos al año en el mundo y se estima que el número de intentos de suicidio es 10 o 20 veces superior. El objetivo del presente trabajo es la evaluación de la efectividad en la reducción de reintentos de suicidio en un Programa de prevención de conducta suicida: el Programa de Intervención Intensiva (PII). Metodología: Se realiza un estudio en el que se compara una cohorte de pacientes expuestos a la intervención en PII con otra cohorte de pacientes expuestos a terapia convencional. La muestra está formada por un total de 191 pacientes, 89 del grupo de tratamiento en PII y 102 pacientes del grupo de tratamiento convencional. Con un seguimiento de 12 meses. Resultados: un 20,6% de los pacientes que recibe tratamiento convencional recaen frente al 10% del grupo de tratamiento en PII (p=0,047). Los pacientes atendidos en el programa presentaron un riesgo menor 2,88 veces de recaída (p=0,015), esto es independiente del número de intentos previos, edad, sexo, necesidad de ingreso tras el intento índice y diagnóstico agregado. Conclusiones: Los resultados muestran que los sujetos que reciben tratamiento en el PII tiene menos reintentos, necesitan ingresar menos, y el tiempo trascurrido desde el inicio del tratamiento y el primer reintento es mayor (AU)

Introduction: Suicide is a public health problem. Consumed suicides reach 1 million cases per year worldwide and it is estimated that the number of suicide attempts is 10 to 20 times higher. The aim of this study was to evaluate the effectiveness in reducing repeat suicide attempts in a program for the prevention of suicidal behavior: Intensive Intervention Program (IIP). Methods: We performed a study that compared a cohort of patients exposed to IIP intervention with another cohort of patients exposed to conventional therapy. The sample was made up of 191 patients, 89 in the treatment group and 102 patients in conventional treatment group, with a 12-month follow-up. Results: Relapse occurred in 20.6% of patients receiving conventional treatment relapse compared with 10% in the treatment group (p=0.047). Patients treated in the program had a 2.88 times lower risk of relapse (p=0.015), this being independent of the number of previous attempts, age, gender, need for admission after the index attempt and aggregated diagnosis. Conclusions: The results show that subjects who are treated in the IIP relapse less, need fewer admissions and the time elapsed between the treatment and the first repeat suicide attempt is greater (AU)